Seat folding apparatus with a passive radio frequency link and foreign object detection system

ABSTRACT

A seat folding apparatus is provided with a passive Rf frequency link that requires that a person be within a certain limited distance from the vehicle to operate the seat folding mechanism. A foreign object detection system, such as a plurality of weight sensors, is provided in the seat to detect foreign objects on the seat.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. application Ser. No. 11/161,028filed Jul. 20, 2005 now U.S. Pat. No. 7,289,035.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic control system for avehicle seat that is convertible between different positions such as aseat position and a load floor position.

2. Background Art

A wide variety of vehicle seating arrangements are available for vans,minivans, and sport utility vehicles (“SUVs”). Vehicle seating systemsmay add versatility to vehicles that is derived from the ability toprovide different seating configurations. Vehicle seating systems mayinclude seats that are used in a conventional seating configuration ormay be converted to provide a full or a partial load floor for haulingcargo. Some minivans are provided with removable seats that arereleasably connected to anchoring devices secured to the vehiclecompartment pan. More recently, seats are available that may fold intorecesses in compartment pans to provide a continuous load floor withoutthe need to remove the seats from the vehicle. Some seats are foldableinto a console position with the seat back being folded forward over theseat base.

Most vehicle seating systems are manual and require a person to releasea lever and reposition various portions of the seat to convert the seatto different modes. A recent innovation is the introduction of powerfolding seats such as that disclosed in U.S. Pat. No. 6,540,295 that isassigned to the assignee of this application. The power folding seatdisclosed in this patent includes an electric motor that rotates theseat back between an upright, slanted seat back position and a generallyhorizontal load floor position. The motor used to fold the seat may beprovided with a voltage regulator that monitors the voltage across themotor that may increase if a foreign object is encountered by the seatas it is moved by the motor. If a foreign object is contacted by theseat, the seat folding mechanism may attempt to continue the foldingoperation until the motor stalls. The motor stall condition is detectedby the voltage regulator that interrupts operation of the motor. Foldinga seat into a foreign object may damage the seat or the object.

The '295 patent also discloses the concept of operating the powerfolding seat upon receipt of an RF signal from an RF transmitter such asa key FOB. The '295 patent also discloses that location sensors may beprovided upon various parts of the seat structure to be sure that themovable panels of the seat system are in the proper position for a givenfolding operation.

The seat system disclosed in the '295 patent is currently in productionas the 2005 Cadillac SRX® sport utility vehicle. As currently produced,the seat has a manually actuated switch that must be held in to completethe folding operation. If the operator releases the switch during thefolding operation, the seat folding operation is immediately interruptedto prevent damage to the seat folding mechanism or objects located on oraround the seat. Some customers have indicated the desire to provide apower folding seat that does not require them to continuously hold theseat actuation button during the seat folding operation. Yet it isdesirable to have an operator near a power folding seat as it folds toavoid problems that may be observed by a person as the seat is foldedand unfolded. There is a need for a power seat folding system that doesnot require an operator to continuously hold a switch during an entireseat folding operation but will not operate unless the person is withinclose proximity to the vehicle during the folding operation.

Another problem associated with power seat folding mechanisms is that nofeedback is typically provided to a user in the event the seat foldingoperation is unsuccessful. If, for example, the seat folding mechanismengages a foreign object and the motor stalls, the operator may notunderstand why the seat folding operation was interrupted. The operatoralso may not understand why the seat did not completely fold if the seatfolding operation begins, but then terminates because the operatorfailed to continue to hold the button in during the entire foldingoperation. An operator may return the vehicle for service when noservice is actually necessary if they do not understand why the seatfolding operation was interrupted. There is a need for a power foldingseat system that provides feedback to an operator in the event a seatfolding operation is interrupted or to confirm that a seat has beenmoved to its fully folded or fully upright position for use as a seat.

These and other problems are addressed by Applicants' invention assummarized below.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a system forcontrolling movement of a power-driven seat folding apparatus in avehicle is disclosed. A motor that drives the seat folding apparatus iscontrolled by an electronic seat control module. The system comprises aplurality of weight sensors disposed on the seat base that provide aforeign object signal to the electronic seat control module when aforeign object of more than a predetermined weight is disposed on theseat base. The electronic seat control module provides an interruptsignal to the power-driven folding apparatus that stops operation of thepower-driven folding apparatus after the foreign object signal isreceived from one or more of the weight sensors.

According to other aspects of the invention, the electronic seat controlelectronically monitors the plurality of weight sensors to sum anelectrical characteristic of each of the weight sensors. The seatcontrol monitors change in the sum prior to or during operation of thepower-driven folding apparatus to detect the foreign object on the seat.During operation of the power-driven folding apparatus, if a lightweightobject of less than the predetermined weight is disposed on the seat,but is pressed against the seat, added pressure is applied to the seat.If the added pressure meets or exceeds the pressure applied by theforeign object of more than the predetermined weight, a foreign objectsignal may be provided to the electronic seat control module.

According to other aspects of the present invention, a plurality ofweight sensors may be secured to a substantially rigid support structureof the seat that supports a foam bun with the weight sensors beingdisposed below the foam bun. The weight sensors may be attached to atray that is installed on top of the support structure. Alternatively,the support structure may have at least one opening and the plurality ofweight sensors may be attached to a sensor tray that is installedbeneath the support structure with the weight sensors aligned with theat least one opening or openings.

According to other aspects of the invention, the electronic controlmodule may monitor the weight sensors until a desired position isobtained at the end of a seat folding operation.

A switch for initiating operation of the power-driven folding apparatusmay establish a latched circuit for the folding apparatus that isreleased when the seat folding operation is completed. The latchedcircuit may also be released in the event the foreign object signal isreceived by the control module. A seat folding operation also may beprevented in the event an ignition key is placed in the vehicle ignitionswitch.

At least one manually actuated switch may be actuated to override thepower-driven folding seat operation and allow manual folding of theseat.

According to another aspect of the invention, an operator perceptibleoutput mechanism is provided that communicates status informationregarding the status of the power-driven folding apparatus in the eventoperation of the power-driven folding apparatus is interrupted. Theoperator perceptible output mechanism may be a display panel on a keyfob Rf transmitter or on the vehicle dashboard. The operator perceptibleoutput mechanism may also be an audio output.

According to another aspect of the present invention, a system forcontrolling movement of a seat disposed in a vehicle that has apower-driven folding apparatus controlled by an electronic seat controlmodule is provided. The system comprises a manually actuated switch thatis actuated to initiate operation of the power-driven folding apparatus.The switch may be released after actuation during operation of thepower-driven folding apparatus without effecting operation of theapparatus. A transponder is carried by a user of the vehicle. Atransmitter/receiver communicates with the transponder and provides aproximity signal when the transponder is within a limited distance fromthe transmitter/receiver. The proximity signal is provided to theelectronic seat control module. The electronic seat control moduleprevents operation of the power-driven folding apparatus when noproximity signal is provided to the electronic seat control module.

According to other aspects of the method of the invention, thetransponder may be part of a passive entry Rf system that is operativeto unlock the vehicle when the proximity signal is received. Operationof the power-driven folding apparatus is permitted to continue untilcompleted unless the transponder is moved beyond the limited distancefrom the transmitter/receiver.

The transponder may have a plurality of manually-actuated switches thatmay be actuated to stop operation of the power-driven folding apparatusduring operation of the apparatus. Alternatively, a manually actuatedswitch may be assembled to the vehicle and may be actuated to stopoperation of the power-driven folding apparatus during operation of thefolding apparatus.

An operator perceptible output mechanism may be used to communicatestatus information to the user regarding status of the power-drivenfolding apparatus in the event the electronic seat control moduleprevents operation of the power-driven folding apparatus.

These and other aspects of the present invention will be betterunderstood in view of the attached drawings and the following detaileddescription of the illustrated embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially fragmented top plan view of a vehicle having threerows of seats with the third row of seats being provided with an arrayof weight sensors;

FIG. 2 is a diagrammatic side elevation view of the rear seat of avehicle having a child seat disposed in the rear seat and also showingthe rear seat in several different positions;

FIG. 3 is an exploded perspective view of a row of vehicle seatsprovided with a pair of arrays of weight sensors;

FIG. 4 is an exploded perspective view of an alternative embodiment of arow of vehicle seats provided with a pair of arrays of weight sensors;and

FIG. 5 is a schematic representation of a seat control system madeaccording to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, a vehicle 10 such as a minivan, sport utilityvehicle, or other vehicle having seats that may be folded into acargo-carrying configuration is illustrated. The vehicle shown in FIG.10 has a first row of seats 12, a second row of seats 14, and a thirdrow of seats 16. The roof 18 and hatchback 20 of the vehicle 10 ispartially cut-away in FIG. 1 to reveal the third row of seats 16. Thethird row of seats 16 is provided with a plurality of weight sensorarrays 24. For example, the third row 16, as illustrated, has threeweight sensor arrays 24 that are disposed in the base 30 of the thirdrow seat 16. The back 32 of the third row seat 16 is shown in itsgenerally upright or seating position.

Referring to FIG. 2, a third row of seats 16 is shown with a child seat36 in the seat 16. Child seats 36 are provided for transporting childrenand infants in a vehicle. Child seats 36 are generally left in a vehiclewhen not in use and may be forgotten if an operator is not careful whenusing a power-folding seat. With manual folding seats, the operator mustunlock and release the seat parts to fold the seat and will ordinarilybe able to observe foreign objects such as a child seat 36 as the seatis folded into a cargo-carrying position. With recently developedpower-folding seats, the seat folding operation begins with a push of abutton, but an operator may forget that a child seat or other foreignobject is on the seat. If a power-folding seat engages a foreign objectas it is moved, it may damage the seat, the seat folding mechanism, orthe object.

FIG. 2 shows a third row seat 16 that includes a base 30 and a seat back32 that are shown in solid lines in an upright position and is shown indashed lines in a partially folded position, and phantom lines in afully folded position. In the upright position, the child seat 36 issecured to the seat 16. As the seat begins to fold, the seat back 32rotates in a counterclockwise direction, as shown in FIG. 2, to aposition that would cause interference with the child seat 36 unless thechild seat 36 is removed. The seat folding operation continues with theseat back 32 rotated so that load floor segment 44 is in a horizontaland lowered position with the foam portion 42 of the seat back 32disposed in the rear stowage well 40. In this position, the load floorsegment 44 forms part of the load floor 46 of the vehicle 10.

Referring to FIG. 3, a rear row of seats 16 is shown to include a base30 and a back 32. The base 30 includes a foam bun that forms asupporting seat body that is covered by fabric, vinyl, or leather, as iswell known in the art. Two weight sensor arrays 24, made according toone embodiment of the invention, include a seat base support panel 50and a plurality of weight sensors 52. The weight sensors 52 aresupported on two trays that hold the weight sensors 52 in openings 58formed in the seat base support panel 50. The weight sensors 52 areoperatively connected to electronic seat controller 60. The electronicseat controller 60 is interfaced with the seat control system, as willbe more fully described with reference to FIG. 5 below.

Referring to FIG. 4, an alternative embodiment of the rear seat 16 isshown to include a seat base 30 and seat back 32, as previouslydescribed. The alternative embodiment of a seat base support panel 62shown in FIG. 4 supports weight sensors 64 that are retained on twotrays 66. The weight sensors 64 are interfaced with seat controller 68.

In FIGS. 3 and 4, the weight sensors 52 and 64 are used to sense thepresence of a foreign object on the seat 16. If a foreign object of morethan a predetermined weight is placed on the seat base 30, the weightsensor will provide a signal to the seat controllers 60 and 68. Ifduring a seat movement procedure a lightweight object is on the seat andpressed against the seat, a signal may also be sent to the seatcontrollers 60 and 68.

Referring to FIG. 5, a seat control system 70 is shown diagrammatically.Operation of the seat control system 70 begins by actuating a controlswitch 72. Control switch 72 may be provided on the vehicle in one ormore locations to allow operation of the seat folding system 70 bypressing a button on the dash or near a door. The control switch 72 mayalso be provided on a key fob, if desired.

A microcontroller 76 controls operation of the seat control system 70 tooperate a seat control circuit 78. Seat control circuit 78 controls oneor more motors 80 that drive linkages supporting different parts of theseat 16. Instead of an electric motor 80, the motor could be a linearmotor or cylinder, depending upon the design of the seat 16.

A plurality of seat sensors 82 that may be arranged in an array ofweight sensors 24 sense the presence of a foreign object on the seat 16.The seat sensors 82 may be load cells or may be spring-biased elementsthat provide an output signal when an object of more than apredetermined weight is placed on the seat 16. The seat sensors 82 mayalso be actuated by a lightweight object that is not more than thepredetermined weight required to trigger the sensors. The lightweightobject when contacted, or pinched, by the seat folding mechanism mayprovide an indication of a foreign object on the seat. For example, ifthe seat back 32 pivots to the position shown in dashed lines in FIG. 2,a lightweight object may be pressed into engagement with the seat base30 sufficiently to cause the seat sensors 82 to provide an indication ofa foreign object on the seat.

A passive Rf receiver 84 establishes a limited area around the vehicle10 in which Rf communication with a transponder 90 may occur. Thelimited area is shown in FIG. 1 as a cross-hatched area surrounding thevehicle and extending around the vehicle, for example, from 4 to 10 feetaway from the vehicle.

The microcontroller 76 is connected to the vehicle bus by aseat-to-vehicle bus interface 86. Bus circuitry 88 is provided in theseat control system to integrate the seat electronics with vehicleelectronics.

The transponder 90 may be part of a key fob-type device. The transponder90 includes a coil and an integrated chip that provides Rf communicationwith the passive Rf receiver of the vehicle. Whenever the transponder 90is within the limited range of the Rf receiver, the transponder may beturned on and provide a Rf signal to the passive Rf receiver 84. Whilethe transponder 90 is within range, the seat control system 70 permitsthe microcontroller 76 to operate the seat control circuit and themotors 80 that drive the seat folding mechanism.

A feedback apparatus 92 is provided as part of the seat control circuit78 to provide an operator perceptible output that can warn the operatorthat the seat folding operation was not completed. The feedbackapparatus 92 may provide an indication that a foreign object is on theseat or another reason for the failure of the seat to complete its seatfolding operation. For example, the feedback apparatus may provideinformation to advise the operator that the seat folding operation wasinterrupted because the transponder 90 was moved outside of the limitedtransmission zone of the passive Rf system. The feedback apparatus 92may be provided on the vehicle dash as a text message or warning light.Alternatively, the feedback apparatus 92 may be part of the transponder90 that can provide a message in the form of an icon or text messageindicating the status of the seat control circuit 78. The feedbackapparatus 92 could also be an audio output such as a voice message thatis transmitted over the vehicle audio system. In another alternative,the feedback apparatus 92 could be a telephone dialer that dials atelephone number of an operator's cell phone to provide an audio orvisual message as to the status of the seat control circuit 78 orposition of the seat 16.

While embodiments of the invention have been illustrated and described,it is not intended that these embodiments illustrate and describe allpossible forms of the invention. Rather, the words used in thespecification are words of description rather than limitation, and it isunderstood that various changes may be made without departing from thespirit and scope of the invention.

1. A system for controlling movement of a seat disposed in a vehiclethat has a power-driven folding apparatus with a motor that iscontrolled by an electronic seat control module, the system comprising:a plurality of weight sensors disposed on a seat base that provide aforeign object signal to the electronic seat control module when aforeign object of more than a predetermined weight is disposed on theseat base; a switch for initiating operation of the power-driven foldingapparatus that is released when a seat folding operation is completed,or the foreign object signal is received by the control module; and theelectronic seat control module providing an interrupt signal to thepower-driven folding apparatus that prevents operation of thepower-driven folding apparatus after the foreign object signal isreceived from one or more of the weight sensors.
 2. The system of claim1 wherein the electronic seat control electronically monitors theplurality of weight sensors to sum an electrical characteristic of eachof the weight sensors and also monitor changes in the sum prior to orduring operation of the power-driven folding apparatus to thereby detectthe foreign object on the seat.
 3. The system of claim 1 wherein theforeign object signal may be provided if a lightweight object of lessthan the predetermined weight is disposed on the seat and the operationof the power-driven folding apparatus causes the lightweight object tobe pressed against the seat to the extent that the pressure applied tothe weight sensors meets or exceeds the pressure applied by the foreignobject of more than the predetermined weight.
 4. The system of claim 1wherein the plurality of weight sensors are secured to a substantiallyrigid support structure of the seat that supports a foam bun and theweight sensors are disposed below the foam bun.
 5. The system of claim 4wherein the plurality of weight sensors are attached to a sensor traythat is installed on top of the support structure.
 6. The system ofclaim 4 wherein the support structure has at least one opening and theplurality of weight sensors are attached to a sensor tray that isinstalled beneath the support structure with the weight sensors beingaligned with the at least one opening.
 7. The system of claim 1 whereinthe electronic control module monitors the weight sensors until adesired position is obtained at the end of a seat folding operation. 8.The system of claim 1 wherein movement of the seat is prevented in theevent an ignition key is in the vehicle ignition switch.
 9. The systemof claim 1 wherein at least one manually actuated switch may be actuatedto override the power-driven folding seat operation and allow manualfolding of the seat.
 10. In the system of claim 1, further comprising anoperator perceptible output mechanism that communicates statusinformation regarding the status of the power-driven folding apparatusin the event operation of the power-driven folding apparatus isinterrupted.
 11. The system of claim 10 wherein the operator perceptibleoutput mechanism is a display panel on a key fob Rf transmitter andreceiver system.
 12. The system of claim 10 wherein the operatorperceptible output mechanism is a display panel on the vehicle.
 13. Thesystem of claim 10 wherein the operator perceptible output mechanism isan audio output.